1. Field of the Invention
This invention relates to a semiconductor memory device having bipolar transistors.
2. Description of the Related Art
Conventionally, a bipolar transistor has been used as a current amplifying element which receives a base current as an input and outputs a collector current. For example, when a positive collector-emitter voltage V.sub.CE and base-emitter voltage V.sub.BE (V.sub.CE &gt;V.sub.BE) are applied to an NPN bipolar transistor, a collector current I.sub.C takes amplified positive values with respect to various values of base-emitter voltage V.sub.BE, and in this case, base current I.sub.B is also positive. Since the conventional bipolar transistor described above can only perform a predetermined operation, the application field of this type of bipolar transistor is limited.